1. Field of the Invention
This invention concerns fuel-efficient vehicles, and more particularly relates to automobiles having multiple power sources which are continuously interactive in a manner to serve the operational needs of the automobile in acceleration, cruising and hill-climbing.
2. Description of the Prior Art
Considerable attention has been directed in recent years toward the development of “hybrid” vehicles having improved fuel efficiency. Such hybrid vehicles generally have an internal combustion engine, and an electric motor adapted to augment the output of the internal combustion when additional power is needed. Re-chargeable storage batteries on the vehicle energize the electric motor.
The hybrid vehicles generally require severe down-sizing of the internal combustion engine to achieve the sought fuel efficiency for cruising operation, namely travel of the vehicle at substantially constant speed on a reasonably non-hilly road. The batteries must be of high amperage capacity with associated control components in order to adequately power the motor. Such requirements result in high initial cost and high maintenance costs as well as problems related to availability of repair and other services. These added costs are often not fully offset by the savings attributable to fuel efficiency. For instance, the additional cost of the batteries alone is often not yet fully offset by the savings in fuel costs before these expensive batteries reach the end of their useful life and would need to be replaced. Non-hybrid fuel-efficient vehicles also have problematic balances between operating costs and purchase price.
U.S. Pat. No. 6,179,078 to Belloso discloses a fuel-efficient and inexpensive automobile having two engines, each coupled to a drive wheel by way of a continuously variable ratio torque converter. Both engines are used for acceleration or hill-climbing, then either engine is used for economical cruising. One disadvantage of this system is the limited power capacity and speed range of current continuously variable ratio torque converters, especially when used for acceleration and hill-climbing.
U.S. Pat. No. 6,637,283 to Belloso discloses a Control Apparatus for a Continuously Variable Transmission (CVT) which increases its operational speed range, adds reverse functionality and provides means for it to accommodate two separate power sources. It does not improve its power handling capacity.
U.S. Pat. No. 4,439,989 to Yamakawa discloses a system wherein two or more engine units are each coupled to a transmission through an electromagnetic power clutch. The system includes means for operating the engines at a proper phase difference of, preferably, 180 degrees to prevent unwanted vibrations. This system is complex and is not readily adaptable for use in automotive vehicles, particularly for the particular purpose of improving fuel efficiency.
Other disclosures of wheeled vehicles employing multiple engines or motors are found in U.S. Pat. Nos. 4,481,841; 4,306,630; 4,475,611; 5,253,724; and 5,429,543.
U.S. Pat. No. 2,462,902 to Rockwell, et. al., discloses a vehicle with a main engine that drives the rear axle and a booster engine that drives the front axle. The main engine is associated with a power train having a clutch, speed change transmission, propeller shaft, two-speed rear axle drive gear, and differential. The booster engine has a power train consisting of a clutch, speed change transmission, propeller shaft, disengageable rear drive, and differential. Although the dual engines of Rockwell, et. al., provide some versatility of operation, particularly when the main engine is overloaded and requires the added power of the booster engine, the several required power train components increase the cost and weight of the vehicle, and do not necessarily improve fuel efficiency.
None of the aforesaid disclosures provide a simpler and more cost-effective way to improve the fuel efficiency of automotive vehicles, particularly for long distance travel on the highways.
It is accordingly a primary object of this invention to provide a simple mechanical alternative to the complex and expensive hybrid system as means for improving the fuel efficiency of automotive vehicles.
It is another object of the present invention to provide a fuel-efficient vehicle through maximal use of the existing power train of current motor vehicles and making only those changes that are minimally necessary to permit the vehicle to travel economically at cruising speeds over long distances.
Yet another object of this invention is to provide a fuel-efficient vehicle of the aforesaid nature employing a minimum of modifications of the power train and integral structure of current motor vehicles, so that the invention can be employed not only in the manufacture of new vehicles, but can also be offered as after-market “add-on” modification of existing motor vehicles.
These objects and other objects and advantages of the invention will be apparent from the following description.